San Francisco police are pleading with the public for help finding a mysterious driver who brutally assaulted a father when he mistook the man's car for a Lyft.

Christopher Matthews, 39, was left with significant head trauma, hemorrhaging and multiple skull fractures.

The father-of-two was with his wife Rebecca, 38, when they called for a Lyft around 11.30pm on September 8.

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San Francisco police are pleading with the public for help with finding a mysterious driver who brutally assaulted father-of-two, Christopher Matthews, 39, when he mistook the man's car for a Lyft

Christopher was with his wife Rebecca (both pictured), 38, when they called for a Lyft around 11.30pm on September 8. Rebecca said her husband was left with significant head trauma, hemorrhaging and multiple skull fractures

Rebecca says his injuries mean he often doesn't recognize her. He has yet to see their two young children since the attack

They were waiting for the ride when Christopher approached a white car, thinking it was the ride.

But it wasn't.

Surveillance video, released by San Francisco police, shows the moment Christopher leaned in for a few seconds before the driver got out.

The driver then punched Christopher hard, causing him to fall straight back and slam his head against the concrete.

The suspect then got back in the car, which has silver rims and a black roof, and sped off.